JP2726599B2 - Engine piston ring - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine (internal combustion engine).
The present invention relates to a piston ring (compression ring) for compression, which causes a decompression action at the time of starting.

[0002]

2. Description of the Related Art In recent years, electric starters (starting motors) for starting have been attached to all engines to facilitate starting. For example, a portable small engine such as a brush cutter is also provided with an extremely small electric starter and a power source such as a dry battery or a similar rechargeable battery (collectively referred to simply as a battery). Starting is in progress.

Even in such a case, it is necessary to reduce the weight of the entire apparatus and to reduce the size thereof. Therefore, it is desirable that the electric starter and the battery are as small and lightweight as possible.

However, even if it is a small engine, since the compression force of the engine at the time of starting is quite large, at present, the electric starter and the battery use relatively large capacity (capacity) having a reasonable weight and volume. Alternatively, by adding a decompression valve mechanism (pressure reducing mechanism) to the engine separately, the compression force at the time of starting is reduced, and the size and weight of the electric starter and the battery are reduced.

As a prior art relating to the decompression valve mechanism, there is Japanese Utility Model Publication No. 64-1488 .

[0006]

However, as described above, if the decompression valve mechanism is separately provided, the weights of the electric starter and the battery are reduced, but the weight is increased by the weight of the newly provided decompression valve mechanism. Increase and also increase in volume. In such cases,
Since the decompression valve mechanism is mechanically complicated, the number of parts, the number of processing steps and the number of assembling steps are increased, so that the manufacturing cost is increased and maintenance is also troublesome.

[0007] Naturally, when the decompression valve mechanism is not provided, the electric starter and the battery become large, and the weight and the volume increase accordingly.

The present invention has been made in view of such circumstances, and focuses on a compression piston ring, which is one of the important factors for generating the compression force of an engine, and exerts a decompression function only when the engine is started. It is an object of the present invention to provide a piston ring.

[0009]

Means for Solving the Problems The first invention (Claim 1)
In the piston ring of the engine according to the described invention), the piston ring disposed in the ring groove of the piston includes a piston ring main body and an auxiliary piston ring for pressing and supporting the piston ring main body, and the function of the auxiliary piston ring In a piston ring of an engine configured to be depressurized at the time of starting, the piston ring is formed such that an outer peripheral surface thereof is in close contact with an inner peripheral wall of the cylinder and an inner peripheral surface of the piston ring forms a gap between the piston ring groove and the bottom surface of the ring groove. A piston ring body of a suitable size, disposed below the piston ring body , and in a state of waving in the vertical direction which is repeated along the circumferential direction at room temperature, the piston ring body is placed between the ring groove upper surface and the lower surface. Support in the play state with a gap,
At the time of high temperature, it becomes flat in the circumferential direction and is supported so as to be in close contact with the piston ring main body, and the outer peripheral surface is in contact with the inner peripheral wall of the cylinder or the inner peripheral surface is in contact with the bottom surface of the ring groove of the piston. It is characterized by comprising an auxiliary piston ring for pressing support, which is dimensioned to create a gap between at least one of them.

[0010] In the piston ring of the engine according to the second invention (invention of claim 2), the piston ring disposed in the ring groove of the piston includes a piston ring main body and an auxiliary pressing support for supporting the same. An engine piston ring comprising a piston ring and configured to depressurize at the time of starting by a function of the auxiliary piston ring, wherein the piston ring has an outer peripheral surface which is in close contact with an inner peripheral wall of the cylinder and an inner peripheral surface which is a ring of the piston. A piston ring body sized to create a gap that serves as a passage between the bottom surface of the groove, and a piston ring body disposed below the piston ring body ;
At room temperature, the piston ring body becomes wavy in the vertical direction repeated along the circumferential direction to support the piston ring main body in a play state having a gap between the upper surface and the lower surface of the ring groove, and at a high temperature, the wavy state becomes more prominent. The piston ring main body is supported in close contact with the upper surface of the ring groove, and a gap is formed between at least one of the outer peripheral surface and the inner peripheral wall of the cylinder or the inner peripheral surface thereof and the bottom surface of the ring groove of the piston. It is characterized by being constituted by an auxiliary piston ring for pressing support of such a size as to be produced.

The piston ring of the engine according to the third invention (the invention according to claim 3) is the same as the piston ring for pressing support in the first or second invention,
The piston ring body has a gap between the upper surface and the lower surface of the ring groove at room temperature by being formed by joining different kinds of metals having different coefficients of thermal expansion or by using a shape memory alloy. It becomes a wavy state in the vertical direction that is repeated along the circumferential direction to support the state, and at high temperatures, the wavy state becomes more prominent to support the piston ring body flat in the circumferential direction or the piston ring body in close contact with the upper surface of the ring groove. It is characterized by having become.

[0012]

According to the piston ring of the engine according to the present invention (first to third inventions ), when the engine is started, the temperature of the piston ring is at room temperature, so that the piston ring main body is located between the upper surface or the lower surface of the ring groove. By being supported in a play state having a gap, between the upper and lower surfaces of the piston ring main body and the upper and lower surfaces of the ring groove, and each inner peripheral surface of the piston ring main body and the auxiliary piston ring and the ring groove bottom surface, Between each other. For this reason, at the time of starting, the combustion chamber and the crank chamber can flow, and the compression force of the engine can be reduced, and a decompression effect can be obtained at the time of starting.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings by taking a two-cycle engine as an example.

[0014] Figure 1 is Ru longitudinal sectional Zudea of a piston showing a state of mounting a piston ring for a two-stroke engine which is the subject of the present invention.

In FIG. 1, reference numeral 1 denotes a piston which can be moved up and down in a cylinder of an engine.
Ring grooves 1A and 1B are formed.

The ring grooves 1A and 1B are provided in FIG.
As shown in FIG. 3, the piston ring 2 is inserted.

In this embodiment, the piston ring 2 is constituted by a piston ring main body 2 'and an auxiliary piston ring 2C for pressing and supporting, and the height of the piston ring main body 2' is the same as that of the ring groove 1A of the piston 1. 1B groove width (Fig.2, Fig.
3) is smaller than the dimension between the upper surface 1a and the lower surface 1b of the ring groove, and is formed below the piston ring main body 2 ', that is, between the piston ring main body 2' and the lower surface 1b of the ring grooves 1A and 1B. Is provided with an auxiliary piston ring 2C. The outer peripheral surface of the piston ring main body 2 ′
The auxiliary piston ring 2C is configured so as to be in close contact with the inner peripheral wall of the cylinder 5, and the outer peripheral surface of the auxiliary piston ring 2C is configured to have a slight gap with the inner peripheral wall of the cylinder 5.

The upper and lower surfaces of the auxiliary piston ring 2C are, at room temperature, as shown in FIG. 2 , the piston ring main body 2 'is formed in the ring grooves 1A, 1B within the ring grooves 1A, 1B.
It is configured to be deformed into a state of waving in the vertical direction that is repeated along the circumferential direction to the extent that it is supported in a play state (disposed in a floating state) having a gap between the upper surface 1a and the lower surface 1b of the I have. In this embodiment, when the engine is in the operating state (high temperature), as shown in FIG. 3 , the upper and lower surfaces of the auxiliary piston ring 2C are flat (the flat state in the circumferential direction as shown), Piston ring body 2 'and lower surface 1b of ring grooves 1A, 1B
Are configured so as to be parallel to.

Therefore, when the engine is started at a normal temperature, as shown in FIG. 2 , the piston ring main body 2 'is inserted into the ring grooves 1A, 1B within the ring grooves 1A, 1B.
Between the upper and lower surfaces of the piston ring main body 2 'and the upper and lower surfaces of the ring grooves 1A and 1B and of the piston ring main body 2'. A gap r is formed between the inner peripheral surface and the bottom surfaces of the ring grooves 1A and 1B.
Will be available for distribution as shown in That is, between the upper surface 1a of the ring groove 1A, 1B of the piston 1 and the upper surface of the piston ring main body 2 ', the bottom surface of the ring groove 1A, 1B, and the inner peripheral surface of each of the piston ring main body 2' and the auxiliary piston ring 2C. During this time, the piston ring body 2 'and the ring grooves 1A, 1B are
The fluid can flow between the combustion chamber and the crankcase side of the engine through the gaps r respectively formed between the lower surface 1b and the lower surface 1b. Therefore, when the engine is started, a decompression action occurs, and the engine can be started with a small force.

Further, when the engine is in operation, the temperature rises at a stretch due to frictional heat and combustion in the combustion chamber, and the upper and lower surfaces of the auxiliary piston ring 2C become flat as shown in FIG. 2 'is the lower surface of ring grooves 1A and 1B of piston 1 via auxiliary piston ring 2C
Since it is supported in close contact with 1b, a predetermined compression state is obtained in the combustion chamber, and a predetermined operation state is obtained.

In the embodiment of the present invention , the upper and lower surfaces of the auxiliary piston ring 2C are configured to be flat at a high temperature and to be in intimate contact with the lower surface 1b of the ring groove 1. It is needless to say that the same effect can be obtained even when the waving state of the auxiliary piston ring becomes larger at a high temperature and the piston ring main body 2 ′ is in close contact with the upper surface of the ring groove.

By the way, as described above, the auxiliary piston ring 2C is a state in which wavy at room temperature, the and configured such that a state of wavy greater than or flat state at a high temperature, two types of thermal expansion It may be configured by joining metals having different rates, or may be configured using a shape memory alloy.

[0023]

According to the piston ring of the engine according to the present invention , at the time of starting the engine, the piston ring forms a gap between the inner circumference of the cylinder and the outer circumference of the piston to cause a decompression action. A piston ring seals between the inner circumference of the cylinder and the outer circumference of the piston to enable smooth operation.

Accordingly, a large force is not required for starting the engine, and the engine can be started with a small electric starter having a small capacity and a battery having a small capacity.

Moreover, in each of the present inventions, since the decompression action is generated only by the piston ring, the size and weight can be reduced as compared with the conventional decompression valve mechanism. It does not prevent conversion.

Further, since the mechanism is simple, the number of parts and the number of assembling steps do not increase, so that it can be carried out extremely inexpensively and maintenance becomes easy.

In addition, since a conventional type other than the piston ring can be used, a decompression function can be easily added to an existing engine.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a piston for a two-stroke engine with a piston ring mounted.

FIG. 2A is a partially enlarged longitudinal sectional view showing a state of a cylinder inner peripheral wall and a piston outer peripheral wall portion at a normal temperature showing a configuration of a piston ring according to an embodiment of the present invention , and FIG. It is.

3 (a) is a partially enlarged longitudinal sectional view showing a state of an inner peripheral wall of a cylinder and an outer peripheral wall of a piston in an engine operating state of a piston equipped with a piston ring shown in FIG. 2 , and FIG. is there.

[Explanation of symbols]

 1: Piston 1A, 1B: Ring groove 2: Piston ring 2 ': Piston ring body 2C: Auxiliary piston ring

 ──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-61-136060 (JP, A) JP-A-55-139242 (JP, U) JP-A-64-21241 (JP, U) JP-A-3-21 28360 (JP, U) JP 3-41078 (JP, Y2) Patent 97960 (JP, C2)

Claims (3)

(57) [Claims] A piston ring disposed in a ring groove of a piston includes a piston ring main body and an auxiliary piston ring for supporting the piston ring, the pressure being reduced at the time of starting by the function of the auxiliary piston ring. A piston ring body having dimensions such that the outer peripheral surface is in close contact with the inner peripheral wall of the cylinder and the inner peripheral surface forms a gap between the piston ring and the bottom surface of the ring groove of the piston. The piston ring main body is disposed below the piston ring main body , and is wavy in the vertical direction which is repeated along the circumferential direction at normal temperature, so that the piston ring main body is in a play state having a gap between the upper surface and the lower surface of the ring groove. Support, so that it is flat in the circumferential direction at high temperature and is in close contact with the piston ring body, and the outer peripheral surface is Dimensioned to produce a gap between at least one of or between the inner peripheral surface for the bottom of the ring groove of the piston and the inner peripheral wall of the cylinder,
A piston ring for an engine, comprising an auxiliary piston ring for pressing support. 2. A piston ring disposed in a ring groove of a piston includes a piston ring main body and an auxiliary piston ring for supporting the piston ring, the pressure of which is reduced at the time of starting by the function of the auxiliary piston ring. In the piston ring of the engine, the piston ring is formed so that an outer peripheral surface thereof is in close contact with an inner peripheral wall of the cylinder and an inner peripheral surface of the piston ring forms a gap between the piston ring and a bottom surface of a ring groove of the piston. A ring body, which is disposed below the piston ring body and is wavy in the vertical direction which is repeated along the circumferential direction at normal temperature to form a gap between the upper surface and the lower surface of the ring groove. At high temperature, the waving state becomes more remarkable at high temperature, and the piston ring body is brought into close contact with the upper surface of the ring groove. With an auxiliary piston ring for pressing support having a dimension such that the outer peripheral surface has a gap between at least one of the inner peripheral wall of the cylinder and the inner peripheral surface thereof and at least one of the bottom surface of the ring groove of the piston. A piston ring for an engine, comprising: 3. The pressing support auxiliary piston ring,
By forming two types of metals having different coefficients of thermal expansion together or by using a shape memory alloy, the piston ring main body can be configured to have a clearance between the upper surface and the lower surface of the ring groove at normal temperature. In the high temperature condition, the waving condition is more remarkable in order to support the piston ring body flat or in close contact with the upper surface of the ring groove at high temperatures. The piston ring of an engine according to claim 1 or 2, wherein: